Open file in visual studio document window on first project load when project is created with custom made project template

Question

I've made a custom project template and when I create a new project in Visual Studio using this template I want to open a file(which belongs to the template) into the Visual Studio's document window(code editor window/whatever...) right after the project is loaded.

If, for example, I create a C# - .NET Framework - Console Application the file Program.cs is opened after the project is fully created and loaded into Visual Studio.
When I use my custom template, no file is opened and the document window is empty.
I would like to achieve the same behavior as it happens for the built-in templates and have a file be opened when the project is loaded

I suspect I would have to edit the .vstemplate file and add some specific tag that would instruct Visual Studio to do that, but I can't find anything useful in the microsoft documentation relating vstemplate element.